The present invention relates to an electric device and a method of optimizing reception of acoustic signals.
Electric devices in the form of telephone terminals that permit voice data entry are already known. Voice data entry is accomplished here by using a hands-free microphone, for example.
A method and an electric device according to the present invention have an advantage in that a characteristic directional effect is achieved by phase-shifted superpositioning of electric microphone output signals. Sensitivity at a given location in space can be improved in this way, so that a sound source arranged there can be picked up especially well by microphones, and interference signal sources at other locations in space can be blanked out. This results in better comprehensibility not only for the human ear in transmission of voice signals over a telecommunications network, for example, but also for a voice processing system with a voice-controlled electric device, so that interference is not picked up from the outset and thus need not be suppressed by complicated measures. The word recognition probability of a voice recognition system is increased accordingly, and word analysis is simplified. There is less distortion of signals by background noise.
It is advantageous that it is possible to set different phase lags on the minimum of one phase delay element. This allows maximum reception to be set for the superimposed signal regardless of location.
It is advantageous that a signal processing unit is provided to receive the electric signals of the microphones and to determine coordinates of at least one sound source as a function of the amplitudes of the electric signals.
In this way, two-dimensional and three-dimensional images of the sound environment can be calculated from the signals picked up, depending on the number and site selection of the microphones, so that the location of all sound sources can be determined. Then the phase lag of the minimum of one phase delay element can be set on the basis of this information in such a way that maximum reception for the superimposed signal is obtained for a desired sound source.
Another advantage is that a voice analysis device is provided for the signal processing unit, and the voice analysis device performs a comparison of parameters of the electric signals with voice parameters stored in a memory unit, and it identifies a sound source as a voice source with a probability value determined as a function of the result of the comparison. The phase lag of the minimum of one phase delay element can be set in this way so as to obtain maximum reception for the superimposed signal at the location of the voice source. Thus, voice signals from this voice source are received with a high sensitivity, whereas interference signals from other sound sources are blanked out.
One particular advantage is that the signal processing unit sets the phase lag of the minimum of one phase delay element as a function of the location of the identified voice source in such a way that maximum reception for the superimposed signal is obtained at the location of the voice source. The phase lag of the minimum of one phase delay element is thus set automatically in this way without the intervention of a user, and the location of the greatest sensitivity can also be corrected adaptively to the site of the voice source. This constitutes a great improvement in operating convenience for the user.